The Variable Refrigerant Flow (VRF) segment is one of the most competitive in the building services industry. And understandably so, given the increasing importance of the technology globally.
What began as the preferred approach to air conditioning in Japan and Asia has expanded dramatically over the past 50 years, in terms of both cooling / heating capacity and range of application. The result is that VRF now competes with chillers as the default solution in many sectors.
As one of the first European countries to adopt VRF, the UK has a reputation for its technical sophistication and high expectations of performance. Installers, consultants and end users are well-informed about the technical aspects and operating characteristics of different systems.
In this context, Toshiba’s latest generation VRF, SMMS-u, pushes forward the boundaries of technology yet again, breaking new ground in terms of efficiency, connectivity, flexibility, compactness and ease of installation.
This is made possible by a number of innovations, including a new triple rotary compressor, developed in-house by Toshiba. This further improves energy efficiency and overall reliability, and with a refrigerant pre-charge almost 50% less than the previous model, it also offers significant safety and environmental benefits.
Efficiency is boosted by the compressor’s multiport design, which operates with outstanding energy efficiency at part load conditions by precisely matching cooling and heating output to the current building load.
In recognition of its efficiency performance and technical achievement, the Japanese Government has awarded SMMS-u the country’s highest technology and business award for products in its home market. The award is supported by the Ministry of Economy, Trade and Industry and organised by the Energy Conservation centre.
In terms of flexibility and connectivity, SMMS-u opens up new opportunities for installers. Total system piping length has been increased to 1,200m, with 250m permissible from the outdoor unit to farthest indoor unit. This makes it possible to apply the system in an even wider range of building types and configurations.
The new maximum height difference of up to 110m between outdoor and indoor units gives project designers greater flexibility. And with a 200% diversity ratio for any single unit and 150% for combined units, the combinations and options possible across buildings are multiplied.
With previous series of VRF systems, the total number of indoor units that could be connected in a single system were limited by the communications protocol. Toshiba has overcome this by developing a new communications platform called TU2C-LINK. This enables up to 128 indoor units to be connected, allowing SMMS-u to be applied in larger buildings.
Performance and efficiency is further improved by a new intelligent, sensor-based defrost system. It continuously monitors the condition of evaporators and only initiates defrost when absolutely necessary. While some other systems lose performance due to frequent defrosts, Toshiba’s system enables SMMS-u to maintain up to five hours of continuous heating, ensuring the comfort of building occupants at all times and reducing energy use.
In applications with multiple systems, the smart control system staggers defrost cycles across the combined systems to maintain optimum overall performance.
We don’t tend to suffer climatic extremes in the UK. However, operating headroom at both the cold and warm ends of the ambient spectrum is important, as it gives air conditioning systems the ability to maintain performance and efficiency, whatever the weather. Therefore, it is reassuring to know that SMMS-u can continue operating in ambients from minus 25°C (for heating operation) to 52°C (for cooling operation), ensuring building comfort whatever the external conditions.
Over time, while building heat loads have gone up, plant room and roof space real-estate has become ever-more precious due to competing uses. To help address this, outdoor condensing units on SMMS-u have a completely redesigned and super-compact chassis. This enables greater cooling and heating power to be deployed in restricted space situations, and significantly improves logistics and handling on site for installers.
Ease and speed of installation were key design criteria for SMMS-u. For example, a new oil management system ensures continuous compressor lubrication and overcomes the need for piping an oil balance circuit, speeding up installation on site.
Access to system information and start test-runs via Toshiba’s Wave Tool Advance app gives installers rapid access to commissioning and performance data. A new intuitive service tool for use with laptop devices can be accessed from both outdoor or indoor locations.
Development is not confined to the outdoor side of the system. In addition to the full range of indoor units that can be connected to SMMS-u, including cassettes, ducted units, and ceiling, high-wall and console units, Toshiba has developed a new one-way cassette with ultra-slim chassis, motion sensor and advanced filtration as an option for high indoor air quality (IAQ), further extending applications.
Believed to be one of the most compact units of its kind available, the new cassette is ideal for use in restricted space applications and small areas, such as offices, local shops, dental surgeries and reception rooms.
In total, some 2,000 different system configurations can be created to precisely meet customer requirements in terms of efficiency, capacity, refrigerant quantity and footprint.
The first-generation of Toshiba’s SMMS (Super Modular Multi System) VRF was launched in 1986. Today, the seventh-generation, SMMS-u, pushes efficiency, adaptability and connectivity to new levels, delivering class-leading performance in the highly competitive VRF sector.
It can now be applied in almost all commercial buildings, new build or refurbishment, and represents a full heating/cooling packaged solution that brings significant advantages to all stakeholders.